Many consumer devices are now constructed to generate and/or use digital data in increasingly large quantities. Portable digital cameras for still and/or moving pictures, for example, generate large amounts of digital data representing still images, video clips, and for some devices audio tracks. To provide for this type of data storage application, the storage memory should be relatively low in cost for sufficient capacities of around 10 MB to 1 gigabyte (GB) or more. The storage memory should also be low in power consumption (e.g., <<1 Watt) and have relatively rugged physical characteristics to cope with the portable battery powered operating environment. Preferably the memory should have a short access time (preferably less than one millisecond) and moderate transfer rate (e.g., 20 Mb/s).
One form of storage currently used for application in portable devices such as digital cameras is flash memory. Flash memory meets the desired mechanical robustness, power consumption, transfer, and access rate characteristics mentioned above. However, the read/write speeds of flash memory cards varies greatly from card to card, vendor to vendor, and for individual cards read/write speeds can degrade with age and/or use of the card. The variance in data transfer rates to/from a particular external memory medium can make certain features unavailable in such applications, for example streaming video at the highest resolution and frame rate acquirable on a digital camera.